Paper machine and apron therefor



Jan. 9, 1923. 7 1,441,332.

P. E. DUDLEY ET AL. PAPER MACHINE AND APRON THEREFOR.

FILED JUNE I6, 1921.

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55 fl; eiraffome Patented Jan. 9, l@23.

1 cans sta rs lipid-@1 33 PHILIP E. DUDLEY, OF WILMINGTON, DELAWARE, AND HARRY BOICE, OF NEW- IB'URGH, NEW YORK, ASSIGNORS TO I. DU FONT DE NEMOUBS & COMPANY, OF "WIIJLVIINGTON, DELAWARE, A CORPORATION OF DELAWARE.

PAPER MACHINE AND APRON THEREFOR.

Application filed June 16, 1921. Serial no. 477,902.

To all whom it may concern:

Be it known that we, PHILIP E. DUDLEY, a citizen of the United States, and residing at Wilmington, county of New Castle, State of Delaware, and HARRY Boron, a citizen of the United States, and residing at Newburgh, countyof Orange, State of New York, have invented a certain new and useful Paper Machine and Apron Therefor, of which the 10 following is a specification.

This invention relates to paper machines and to aprons therefoi and more particularly it relates to a paper machine of the Fourdrinier type which while havinga rell5 atively' inexpensive and long wearing means for conducting the pulp to the screen and spreading it thereon, will at all times deposit the pulp mixture on the screen smoothly and evenly, with the result that 29 paper of uniform thickness will at all times be produced. 'A Fourdrinier paper machine, as is well understood in the art, comprises a flow boat at the wet end of the machine for the pulp mixture from which the paper is to be made, and a travelling screen onto which the pulp-and-water mixture is flowed from the flow box. The water drains through the screen leaving the pulp thereon, thus beginning the actual converting of the 30 pulp into paper. One of the problems of the papermaker is to transfer .the pulp from the flowbox to the screen in such a manner that the pulp will be deposited on the screen in an even sheet, for the slightest unevenness in the deposit will result in an uneven product. I

7 We have devised a paper machine in which not only is the pulp evenly deposited, but

. furthermorethe depositing means is always 40 in condition for use, relativelyinexpensive.

long-wearing and maintains its efficiency \over long periods. It isthe object of our invention to provide such a machine and such means, said means being, specifically, an apron of thecharactechereafter set forth.

In the accompanying draw1ngs:-

Figure 1 is a conventional exaggerated cross-sectional view of an apron made in accordance with our invention, and

Figure 2 is a simplified somewhat dia grammaticplan View of the wet end of a paper machine embodying our lnventioni, the remainder of the machine being omitted to economize space.

Referring more particularly to Figure 2, the illustrated Fourdrinier machine comprises the flow boxvand its discharge frame or trough, together designated as 1, the endless Fourdrinier screen 2 supported by the breastroll 3 and travelling (at its illustrated top span) in the direction of the arrow, the deckels 4:, the slices 5, and the flexible apron A supported by the frame or trough by being smoothly spread thereover and fastened thereto as by tacks (not shown) and covering the trough and bridging the gap between the end 1? of the trough and the screen. The apron not only covers the trough, and bridges the gap between the end 1 and the screen, the end 1 of course being vertically above and clear of'the screen, but it also extends along the screen into proximity to the slices and rests (at A directly on the screen; and thus the apron serves to conduct the pulp mixture from the flow box to the screen and to deposit it upon the screen.

According to our invention the apron is of textile fabric thoroughly, and substantially uniformly throughout its thickness, impregnated with a water-proofing substance, i. e., pyroxylin. The impregnation is such that the individual fibres as well as the threads are sealed in and protected from water by pyroxylin, and the interstices be tween the components are substantially filled with pyroxylin. With the pyroxylin is used such fleXibility-imparter, or softener, as will ensure that the apron shall lie smoothly on the screen, and so forth. Preferably a pigment is also used with the pyroxylin. Desirably the fabric is not only impregnated but is also smoothly coated with pyroxylin. In this way we provide a paper machine in which the pulp mixture will at all times be deposited evenly; and yet the machine has a relatively inexpensive non-deteriorating and long wearing apron.

While the machine is running the apron is of course constantly kept wet and, were the apron of mere textile fabric, the. fibre in the cloth would become thoroughlywater soaked and, then, when the machine was stopped, and the fabric exposed to the air. the fibres wouldshrink and as a result a buckle or hump would appear in the apron. A. buckle will cause the layer ofmixture fed to, and deposited on, the screen to be of uneven thicknew because of the mixture being shallow above the rise of the buckle and deeper at each side. Even were the fabric coatedon its faces with a waterproofing material it would still buckle, as the exposed edges, particularly that lying crosswise ofthe screen, would yet be unprotected and permit the water to soak into the goods. Also the coating would soon wear off from the fabric, especiallyon that portion of its face resting directly on the travelling screen, andv thus expose the fabric to water" on such face. Yet textile fabric does present advantages such as low cost, flexibility, freedom from rapid deterioration, and so on. With the present apron, of textile fabric waterproofed throughout its thickness, all difficulties such as those mentioned are avoided, and yet the advantages inherent in textile fabric, such as flexibility, relatively small cost, relative freedom from deterioration with age, and so forth, are retained. Furthermore, since the fabric of the present invention is long wearing, replacement expense, which is made up not only of the cost of the material but also, of the timeloss due to stopping the machine, is reduced to a minimum.

An apron embodying the above advantageous features may be made in various ways and, by way of example, it may be made as 'follows, the procedure, inbrief, consisting in first thoroughly impregnating the fabric substantiall uniformly throughout its thickness with pyroxylin and then coating it with pyroxylin:The cloth may be cotton sateen grey goods without nap on either side,

and for example, about 55 inches in width and weighing about one-half pound per square yard, that is, one pound per 1.27 running yards of material of the mentioned width. Each side of the fabric is treated with pyroxylin solution to deposit on such side oneto two-tenths pound, preferably fourteen-hundredths pound of pyroxylin per square yard; that is, about one-fifth pound per running yard of the 55-inch goods, such a deposit, with the exemplary proportions of oil and pigment indicated below, carrying with it about thirty-five hundredths pound each of oil and pigment per running yard and iving a total deposit of solids in the neigh orhood of a pound. Any suitable solvent for the pyroxylin may be used, a mixture of 60 parts of benzol and 40 parts of ethyl acetate by weight being satisfactory. For the treating of the fabric with the pri mary purpose of impregnating it a relative- 1y t in solution is used, e. g., a 4 ounce jelly (4 ounces of pyroxlin per gallon of solvent) and for the applications which are more particularly for surface coating a relatively heavy solution is used, e. e a 16 ounce jelly (16 ounces of 'pyroxylin pergallon of'solvent). In the jellies may be used to each pound of pyroxylin, one-andone-half to two-and-one-half, desirably oneand-three-quarters pounds, each of castor oil (softener) and zinc oxid (pigment). It will be understood that other jellies than those mentioned may be used if desired, having in mind the ends sought.

In applying the solutions, the ordinary knife pyroxylin-coating machine with the usual provisions for flowing the solution ,onto the web and for drying the coated web,

may be used. The number of applications will of course vary with the particular mixtures used and the amount of material to be deposited.

First, a suflicient number of applications of the thin jelly is applied to each side of the fabric to thoroughly impregnate it throughout its thickness, say three dull knife coats to each side, the material being dried after each coat. Next, there is applied to each side about half the full number of coats of thick jelly required to bring the deposit up to the required amount, the full number being, for example, six to ten dull knife coats, the material being dried after each coat. Next thematerial is calendered (between steel rolls). Finally the remaining (three to five) coats are applied, using, if called for, tight tension on the goods, and drying after each coat. After the completion of the coating the finished length of the solutions may be applied to but one side of the fabric, the procedure, except for the application to but one side, being in general as just outlined and the goods produced, though impregnated, having a substantial surface coating upon but one side.

We claim:

1.- In a paper machine, in combination, a flow box, a Fourdrinier screen for receiving the flow from said box, and an apron of textile fabric substantially uniformly impregnated throughout. its thickness with pyroxylin, arranged between said box and screen for conducting the flow.

2. In a paper machine, in combination. a flow box, a Fourdrinier screen for receiving the flow from said box. and an apron of textile fabric substantially uniformly impregnated throughout its thickness, and coated, with pyroxylin, arranged between said box and screen for conducting the flow.

3. In a paper machine, in combination. a flow box, a Fourdrinier screen for receiving the flow from said box. and an apron of pyroxylin, arranged between said box and screen for conducting the flow.

4. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness with pyroxylin.

5. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness, and coated, with pyroxylin.

6. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness, and coated on each face, with pyroxylin.

7 An apron for paper machines, of textile fabric coated on each face with like coatings of, and substantially uniformly impregnated throughout its thickness with, pyroxylin.

8. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness with pyroxylin together with a softener.

9. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness with pyroxylin together with a softener and pigment.

10. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness With pyroxylin together with castor oil in the proportion of substantially between one-andone-half and two-and-one-half parts of oil to one of pyroxylin.

11. An apron for paper machines, of textile fabric substantially uniformly impregnated throughout its thickness with pyroxylin together with castor oil and zinc'oxid in the proportions of substantially between one-and-one-half andtwo-and-one-half parts each of oil and oxid to one of pyroxylin.

In testimony whereof we affix our signatures.

PHILIP E. DUDLEY. HARRY BOICE. 

